The present invention relates generally to evaporative coolers for use in gas turbine intake air systems. More particularly, the present invention relates to sumps used with turbine evaporative coolers.
A gas turbine engine works more efficiently as the temperature of the intake air drawn into the gas turbine decreases. Turbine efficiency is dependent upon the temperature of the intake air because turbines are constant volume machines. The density of the intake air increases as the temperature of the intake air drops. Consequently, by decreasing the temperature of the intake air, the mass flow rate to the turbine is increased which increases the efficiency of the turbine.
Evaporative cooling is an economical way to reduce the temperature of the intake air drawn into the turbine. An evaporative cooler commonly includes a plurality of vertically stacked volumes of cooler media. A distribution manifold disperses water over the top of the cooler media. The water is drawn from a sump, distributed over the media by the distribution manifold, and then recycled back to the sump. Intake air for the gas turbine flows through the cooler media. As the water falls or flows through the cooler media, the air passing through the media evaporates some of the water. The evaporation process removes some energy from the air, thereby reducing the temperature of the air.
One aspect of the present invention relates to an evaporative cooler for a turbine air intake system. The evaporative cooler includes a reservoir or sump for holding water, a media, a manifold for dispersing the water from the reservoir above the media, a manifold flow line extending from the reservoir to the manifold, a collector for collecting the water below the media, and a pump for pumping the water through the manifold flow line from the reservoir to the manifold. The evaporative cooler also includes a return line for returning the water from the collector to the reservoir, at least one water supply line for supplying the water to the reservoir, and a valve structure for controlling flow through the at least one water supply line. The cooler further includes a level sensor for indicating whether a top surface of the water within the reservoir is: (1) above or below a first water line; and (2) above or below a second water line positioned below the first water line. A controller of the evaporative cooler interfaces with the valve structure and the level sensor. The controller causes the valve structure to: (1) start water flow to the reservoir at a first flow rate when the top surface of the water falls below the first water line; and (2) increase water flow to the reservoir from the first flow rate to a higher second flow rate when the top surface of the water falls below the second water line.
A variety of advantages of the invention will be set forth in part in the description which follows, and in part will be apparent from the description, or may be learned by practicing the invention. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.